Tuesday, July 31, 2012

July 31, 2012: Storms For Tomorrow, Sunday


Forecast Highlights:

- Locally heavy storms, some strong, for Wednesday
- Temperatures to warm up with more humidity by late week
- Strong/possibly severe storms with cold front on Sun/Mon

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No update will be posted on Wednesday, August 1. The next update will be posted on Friday morning, August 3.

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Monday, July 30 Observations:


A weak high pressure moved into the region on the 30th, resulting in drier conditions following the heavy thunderstorms on the 29th. Temperatures were slightly warmer from NYC and further north/west, reaching the lower to mid 80s, but were slightly cooler in the eastern half, reaching the mid to upper 70s in Long Island and southern CT.





Tuesday, July 31 Observations:

The area remained dry in between two storm systems as a cold front slowly approached the area from the west, affecting Pennsylvania and New York with storms, while a small semi-tropical low pressure moved up the coast to the east, staying east of the area while affecting eastern Massachusetts with heavy rain. Cloud cover from the coastal low pressure to the east affected the eastern half of the area, where temperatures peaked in the lower to mid 70s in eastern areas and mid to upper 70s further west. NYC and north/west reached the lower 80s.


Tomorrow's Outlook: Storms, Some Heavy

A weak cold front will move closer to the area, resulting in mostly cloudy skies and thunderstorms. Scattered storms are expected to develop, mainly north and west of NYC, with tomorrow's storms slow moving, resulting in locally heavy rain totals exceeding 1 inch. Some of the storms could be strong or low-end severe, although most of the storms will remain below severe levels. Temperatures will reach the lower to mid 80s from NYC and further north/west and the upper 70s to lower 80s in Long Island/S CT.


Thursday - Monday: Warmer, More Humid

Partly sunny skies with dry conditions are expected for Thursday, with highs reaching the upper 80s to lower 90s from NYC and further north/west and the mid 80s in most of Long Island/S CT. Another coastal low pressure could develop offshore during Thursday; while at this time, it is expected to stay east of the area, it is not out of the question that clouds and some showers may affect eastern parts of Long Island. A warmer air mass will move in for Friday and the weekend, resulting in warmer temperatures and increased humidity along with an isolated thunderstorm risk for each day. With 850mb temps approaching 20C, Friday and Saturday are expected to be the warmest days, with highs in the lower 90s for most places from NYC and further north/west, with mid 80s to 90 degrees in most of Long Island/S CT. Temperatures on either day may approach and/or reach 95 degrees in parts of the immediate NYC area. Along with humid conditions, heat index values are likely to reach and slightly exceed 95 degrees in the immediate NYC area.

The next cold front will move into the region for Sunday and Monday, resulting in widespread thunderstorms, some of them severe. At this time, the cold front is modeled to move through early on Monday, with a line of storms moving through earlier in the day, although should the front end up a bit slower, there could be a higher risk of severe weather for Monday. Cooler temperatures are likely towards the middle of next week behind the cold front, although more warmth and/or storms are likely to build into the region by late next week and next weekend.

Sunday, July 29, 2012

July 29, 2012: Seasonable Week Ahead


Forecast Highlights:

- Temps start out near-slightly below average, warm up by late week/weekend
- Scattered storms likely for most days this week, next weekend

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The updated hurricane season outlook, along with an August outlook for the NYC area, will be posted on Monday in the Long Range Outlooks page.

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Today's Observations:


The low pressure that moved through the region on 7/28 moved offshore, resulting in widespread cloud cover along with scattered storms over parts of the Northeast. Although the first part of the day was dry, isolated afternoon storms moved through parts of the area in the afternoon and evening. Temperatures ended up cooler than average again, peaking in the upper 70s to lower 80s from NYC and further north/west, and the upper 70s across most of Long Island with Islip, NY and New Haven, CT reaching 80 degrees.



This Week: Seasonable, Scattered Storms

The outlook for this upcoming week doesn't change much from day to day with little significant weather events on a region wide scale. Monday and Tuesday start out mainly dry with isolated storms, especially on Tuesday. Temperatures remain near-slightly below average, in the lower to mid 80s for highs from NYC and further north/west and the upper 70s to lower 80s in Long Island and southern CT. Partly cloudy skies are expected. More widespread thunderstorms are expected for Wednesday and Thursday with similar temperatures still expected, perhaps a bit cooler on Wednesday depending on the amount of cloud cover and rain. Some storms may be strong/severe, although a widespread severe weather outbreak is not expected at this time.

Drier conditions are likely towards Friday and possibly Saturday, although isolated/scattered storms are still not out of the question. By then, however, a warmer air mass will move into the region, with temperatures gradually warming up into the mid to upper 80s, slightly cooler in coastal areas. 90+ degrees are possible in parts of the area towards the weekend time frame, although the risk of thunderstorms returns towards the late weekend and possibly early next week. More information will be posted as details become clearer.

Saturday, July 28, 2012

July 28, 2012: More Storms Next Week


Forecast Highlights:


- Heavy rain, localized flash flooding continue tonight
- Somewhat drier Sun-Tues, isolated showers possible
- More rain returns for Wednesday, next weekend


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Friday, July 27 Observations:

Dry conditions were observed across the area on Friday with the rain mainly staying west. Temperatures peaked in the mid to upper 80s inland, upper 80s to lower 90s in the immediate NYC area, and the mid to upper 80s in Long Island and southern Connecticut. Teterboro had the hottest temperatures with 92 degrees, with New London the coolest station with 85 degrees.




Saturday, July 28 Observations:

A low pressure moved into the region, resulting in widespread thunderstorms across the region. Morning storms were observed in parts of Long Island, with rain amounts locally above 3-4 inches. Afterwards, more storms developed in the afternoon, with a slow moving line of heavy rain and thunder affecting SE NY, Connecticut, and parts of northern NJ. This line resulted in additional heavy rain totals above 1-2 inches. Scattered evening storms developed over eastern PA, although these storms mainly stayed south of the area, with a severe cell moving east through central NJ. Temperatures were cooler due to the cloud cover and rain, peaking in the upper 70s to lower 80s from NYC and further north/west and the mid to upper 70s in Long Island/S CT.



Tonight - Tomorrow's Outlook:


Today has been active across the area in terms of storms, starting out with morning Long Island storms dumping amounts as high as 4 inches in isolated spots. Following the earlier afternoon storms, which produced locally heavy rainfall above 1-2 inches from NYC and further north/west, additional scattered strong storms are developing over western NJ and eastern PA, slowly drifting east. These storms will slowly enter the area, producing heavy rain with localized flash flooding. Some of these storms could be strong to low-end severe with gusty winds and small hail.

The rain and thunderstorms, heavy at times, will continue through tonight and into Sunday morning. Rain totals are expected to end up generally between 1/2 to 1 inch with some areas exceeding 2 inches. The highest totals will stay for the main part north and west of NYC, with lighter totals in Long Island/S CT. Showers and thunderstorms are expected to continue for the first half of Sunday, with drier conditions for the second half of the day but with clouds persisting. Highs will peak in the mid to upper 70s, locally reaching 80 degrees, with the cloud cover and morning rain.


Next Week: Seasonably Mild, More Rain Expected

Dry conditions are generally expected for Monday and Tuesday, although isolated storms are possible on both days. Temperatures are expected to be slightly warmer with partly sunny skies, reaching the lower to mid 80s from NYC and further north/west and the upper 70s to lower 80s in Long Island/S CT. During Tuesday night and Wednesday, more widespread showers and storms are expected to affect the region, with temperatures similar to, if not slightly colder than those of Tuesday.

Scattered storms are possible for Thursday, although the late week period has a somewhat drier look to it with slightly warmer temperatures. As the next low pressure approaches, more showers and thunderstorms are expected around next weekend, although the exact timing and scenario is still uncertain.

July 28, 2012 Noon Update


3:30 PM: Heavy Rain Moves In


Earlier this afternoon, widespread heavy thunderstorms formed over interior SE NY, and are very slowly moving SE into the northern and western parts of the area. A few storms could be strong or low-end severe, with gusty winds and small hail possible, but for the main part little severe weather is expected, with heavy rain the bigger risk.

Due to the slow motion of the storms along with high precipitable water values, flash flooding is expected in some areas north/west of NYC, with amounts exceeding 1-2 inches in some areas. The storms will also get into NYC and Long Island, although the highest rain totals are expected to stay north and west of NYC.

A forecast discussion will be posted later this afternoon, including more information on the additional rain expected for this upcoming week.

Friday, July 27, 2012

July 27, 2012: More Rain For Next Week


Forecast Highlights:


- Additional storms expected for Saturday; mostly dry Sun/Mon
- More rain/thunderstorms return for mid-late next week
- Temperatures to generally remain near-below average


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Wednesday, July 25 Observations:


A cooler air mass briefly moved into the region on the 25th, interrupting the two heat frames before and after 7/25. Mainly sunny skies were observed across the area with temperatures peaking in the mid 80s inland, lower to mid 80s in Long Island/S CT, and in the mid to upper 80s in the immediate NYC area. The warmest temperatures were observed in Newark with a high of 89 degrees.




Thursday, July 26 Observations:


A widespread regional severe weather outbreak took place on the 26th, with a MCS developing over northwestern PA and making its way into New Jersey. The MCS produced damaging winds in northern PA/southern NY, along with a tornado near Elmira, NY. The MCS entered the western parts of the area, producing strong winds and heavy rain, but instead of the storms maintaining their severe intensity until reaching the coast, the storms weakened as they entered the area, with winds ending up below severe criteria for parts of the area, including most of Long Island and NYC. The storms were still strong to low end severe over SW CT and parts of northern NJ, however. Temperatures reached the lower to mid 80s in Long Island/southern CT, mid to upper 80s inland, and the lower to mid 90s in the immediate NYC area, peaking at 95 degrees in LaGuardia. Humid conditions were observed as well, with heat index values reaching the upper 90s to 100 degrees in the immediate NYC area.


Tonight - Weekend: Some Storms, Cooling Down


As of this evening, the area is dry with the rain staying west over northern PA. No widespread storm outbreak is expected tonight, although scattered storms, mainly non-severe, are expected to affect the area tonight. More widespread storms are expected across the region on Saturday, however, with mostly cloudy skies and cooler highs, peaking in the upper 70s to mid 80s across the area. Sunday will be drier with more sunshine expected, although isolated storms are still expected. Highs will reach the upper 70s to mid 80s as well.


Next Week's Outlook: More Rain, Storms


Monday is expected to be mainly dry with slightly warmer temperatures, in the lower to mid 80s for most places. Throughout the rest of next week with a polar vortex stuck over central Canada, a trough will stay in place over the region, with persistent cloud cover and frequent rain chances. Temperatures are generally expected to end up in the lower to mid 80s, which is slightly cooler than average, although may end up in the upper 70s on the stormier days and upper 80s on the drier/sunnier days. Next weekend's outlook is a bit more uncertain but appears somewhat similar to the late week conditions, although less rain is possible.

Thursday, July 26, 2012

July 26, 2012 Storm Updates



Below, updates will be posted on the severe weather outbreak affecting the region today.

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Current Storm Updates (Scroll down for brief Twitter updates)


8:00 PM: Severe Storms Entering NYC


The line has weakened over NE NJ, northwestern Long Island and southern CT, and for the main part is below severe levels, producing brief heavy rain and gusty winds. Further south, however, the line remains severe at this time, with severe storms containing strong wind gusts and heavy rain entering the southern half of NYC including Staten Island, Queens and Brooklyn. These storms will continue to move into the rest of Long Island.

This is the last storm update for the night. A summary on today's storms across the region and the area will be posted on Friday along with a forecast update.


7:40 PM: Storms Weakening


As the storms entered the immediate NYC area, two severe lines held together; a line near Newark currently entering the southern half of NYC, producing strong to damaging wind gusts as well as heavy rain. Similar conditions are affecting southwestern Connecticut. The line weakened over NE NJ and SE NY, ending up below severe levels with brief heavy rain/gusty winds. The area of weaker storms is now moving into northwestern Long Island.


7:15 PM: Storms Approaching NYC


The severe storms  from the MCS have affected NW NJ and interior SE NY, and are now entering the immediate NYC area. Reports from the storms in NW NJ so far included heavy rain and strong wind gusts. The latest radar shows very minor weakening with the northern NJ/SE NY storms, although despite the minor weakening these storms are still severe and capable of producing strong wind gusts and heavy rain. The storms will move through the immediate NYC area over the next 1/2 to 1 hour, later on moving into southern CT and the western half of Long Island.





5:55 PM: MCS About To Enter Area


Since the previous update, the severe storms in northern PA continued to develop into a MCS, and the MCS is about to enter the NW parts of the area in Sussex and Orange counties. These storms are quickly moving to the ESE, with the MCS on target to affect the entire immediate NYC area over the next 2-3 hours, getting into NYC around at least 7 PM and further east afterwards. The storms are still capable of intensifying with an unstable air mass ahead of them.

These storms are NOT to be taken lightly. This severe storm complex is capable of producing wind gusts above 60 mph, hail, heavy rain, and the potential for isolated tornadoes. Risks include downed trees/power lines, widespread power outages, and perhaps additional damages. Stay tuned for additional updates as the storms enter the area starting now through the next 2 hours.


3:45 PM: Storms Over Central PA


Over the last 2-3 hours, the squall line entered Pennsylvania, quickly intensifying with new storms forming to its south. Currently, there is a line full of strong to severe thunderstorms moving east/ESE, with the majority of central/northern Pennsylvania and southern New York state in its path. This line is easily expected to maintain itself until it gets into the NYC area towards around 7-9 PM this evening, producing damaging winds, hail and isolated tornadoes along its path. Similar impacts are expected across at least parts of the area as well. The main storm right now is located over north central PA and is generally moving east/ESE. This part of the squall line will continue to track east/ESE, and will be the main severe weather producer for the area this evening.


1:10 PM: Severe Storms This Evening


Early this morning, thunderstorms left over from a line of severe storms in the Great Lakes moved through the region, producing locally heavy rain especially over northern NJ just south of the NY/NJ border, where radar estimates show amounts locally approaching 1 inch. The morning storms, however, are just a preview of the main show for later tonight. The latest regional radar posted to the left shows most of the storms currently to the north of the area, with otherwise little rain around. The showers in southern NY are currently dissipating as cloud cover is clearing over Pennsylvania and New Jersey, including the area. With the clearing in the cloud cover, temperatures will quickly rise by the mid afternoon hours into the lower 90s from NYC and further west/southwest. Along with humid conditions, heat index values are expected to reach 100 degrees.

With cloud cover clearing up, destabilization is expected to quickly take place with much higher CAPE values, up to 3,500 J/kg, and lift index down to at least -8. Unlike previous severe weather events, the higher shear is located over the higher instability areas, further enhancing the severe weather potential. Widespread storms are expected to develop towards Pennsylvania and Ohio soon, and are easily expected to maintain themselves as they move east through PA and into New Jersey and SE NY, perhaps solidifying into a MCS. The biggest risk with this evening's storms is damaging wind gusts, especially if a MCS does end up developing. Should one develop, central/northern Pennsylvania into central/northern New Jersey appear to be the target area for this to happen, with widespread damaging wind gusts and power outages a threat from today's storms should a MCS develop. Other risks today are heavy rainfall, with precipitable water values over 2 inches, as well as hail. Stay tuned for more information on today's severe weather outbreak with updates throughout the afternoon and evening.


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NYC Area Weather Twitter updates:


Additional updates from this day can be found in the NYC Area Weather twitter page.



Wednesday, July 25, 2012

July 25, 2012: Severe Weather Outbreak Tomorrow


Forecast Highlights:


- Widespread severe weather outbreak possible tomorrow
- Slightly cooler for Fri/Sat with clouds/storms
- More storms possible for next week


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Yesterday's Observations:


Tuesday, July 24 was another warm day across the area, with temperatures reaching the lower to mid 90s for most places except for far eastern Long Island and the interior areas, which peaked in the upper 80s. Newark and JFK reached 96 and 95 degrees, respectively. Most of the day was dry, although scattered storms ended up affecting parts of the area towards the evening hours, especially over southern Connecticut and Long Island.

Following a much more seasonable and dry day today, an approaching low pressure will result in what may be one of the biggest severe weather outbreak of the last few years across the region for Thursday, with the NYC area in the southern edge of the highest severe weather risk. Temperatures will slightly cool down for Friday and Saturday with more storms and clouds, with additional storms possible later next week.


Thursday's Outlook: Severe Storms Likely


A low pressure will move through the region tomorrow, bringing what may be one of the biggest severe weather outbreaks for the region over the last few years. The Storm Prediction Center (SPC) already has the region, including the area, in a Day 2 moderate risk; moderate risks are not very common for the area, especially not 2 days out. The day will start out with scattered morning storms in central New England, possibly extending a bit further south to affect the northern parts of the area. Clearing in the cloud cover is expected by the afternoon hours, with temperatures quickly warming up into the lower to mid 90s from NYC and further north/west, possibly passing 95 degrees in the immediate NYC area. Along with the heat, high humidity is expected as well with dew points likely in the upper 60s to possibly lower 70s, resulting in heat index values reaching and/or slightly exceeding 100 degrees.

By the mid afternoon hours, widespread instability will be present across the region with LI down to -8 and CAPE up to 3500 J/kg; as a low pressure moves towards central NY with the cold front slowly approaching, widespread thunderstorms are expected to form from Ohio into central/northern Pennsylvania and southern New York state. Unlike the last severe weather outbreak, however, there is widespread shear present under the areas of higher instability, especially over the area, in southern NY/northern PA, and in southern New England. This appears to be the main area of concern regarding tomorrow's storm activity, with the main risk including damaging winds, hail, and perhaps isolated tornadoes.

The outlook for the NYC area is a bit more uncertain, however, as some models show the storms not making it far south of the area, keeping the biggest activity to the north/west, although especially if a MCS/derecho ends up forming, which is a possibility also highlighted by the latest SREF runs, the area may have a better risk of observing more widespread severe weather. With the more favorable parameters compared to the last events, I placed a widespread 30% risk zone, with a 45% zone extending from central/northern PA into southern New England. There is some uncertainty on whether the area ends up in the higher risk area or not, although it is a possibility that the 45% risk zone may need to be extended to the coast. Stay tuned for afternoon updates on tomorrow's regional severe storm outbreak.


Longer Range: Storms are expected to continue affecting the region on Friday and Saturday with highs cooling down into the mid 80s to lower 90s across the area. Drier conditions are likely to return by Sunday and the early week before more storms possibly return towards the middle of next week. No significant warm spell or cool down is on track to affect the area.

Tuesday, July 24, 2012

July 24, 2012: Hot, Stormy Ending To Week


Forecast Highlights:


- Very brief cool down for Wednesday only; highs in low-mid 80s
- Heat returns briefly for Thu/Fri; highs on Thu to surge near/above 95
- Severe storms possible on Thursday; more storms Fri-Sat


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Sunday, July 22 Observations:


A slightly warmer air mass moved into the region on Sunday, with temperatures slightly warming up across the region. Highs peaked in the lower to mid 80s from NYC and further north/west, and in the upper 70s to lower 80s in Long Island and southern Connecticut. Although these temperatures are still cooler than average, the negative departures were not as large as they were in the previous days following the chilly rain storm on July 20.



Monday, July 23 Observations:


As a warm front moved through the region, several rounds of thunderstorms were observed during the day focusing north/west of NYC. Morning storms were observed in SE NY extending into SW Connecticut, with amounts locally over 1 inch. After more sunshine in the second part of the day, two severe storms focused over NW NJ, both of them weakening once getting south/east of NW NJ, with only a weakening area of moderate rain moving through the immediate NYC area. Temperatures peaked in the mid 80s to lower 90s from NYC and further north/west, with lower 80s in most of Long Island/S CT except for eastern areas in the upper 70s.


Tonight - Wednesday Outlook:


The outlook originally called for dry conditions today; although the day has been dry so far, scattered storm activity is persisting as it's making its way into the area. Scattered storms, staying below severe levels and quickly moving through, are expected in the evening in parts of the area, especially over southern Connecticut but with isolated storms further west as well.

A cooler air mass will briefly move into the region on Wednesday resulting in slightly cooler temperatures, with highs peaking in the lower to mid 80s across the area along with mainly sunny skies.



Thursday - Saturday: Hot, Humid and Stormy


The forecast becomes much more interesting by Thursday and next weekend as a low pressure and a slow moving cold front affect the region. There is decent agreement with the models for a MCS to move through the region early on Thursday morning; the exact location/timing remain uncertain but although the better potential appears to stay north of the area, morning storms, possibly strong or even low-end severe, are still possible, if not likely for early Thursday morning in the NYC area. Behind the storms, a much warmer air mass will push into the area with 850mb temperatures above 20C, with clearing in the cloud cover allowing for temperatures to warm up into the lower to mid 90s from NYC and further north/west, with slightly cooler temperatures in Long Island/S CT due to more clouds and a delayed impact from the morning storms compared to the western half of the area. Humid conditions are also expected with dew points in the lower 70s, pushing heat index values near or possibly above 100 degrees. Assuming no major changes in the forecast, I will likely issue a heat alert for Thursday with the next update.

By Thursday evening, widespread thunderstorms are expected to form ahead of the cold front which will slowly make its way into the region. The set up is favorable for severe weather with decent instability and supportive shear. The best risk at this time appears to stay to the north and west of the area, but the NYC area is close to the southern end of the severe weather potential for Thursday evening, and the potential will be monitored. Stay tuned for more information on Thursday's heat and severe storm potential.

The cold front will slowly make its way through the region, with cooler temperatures for Friday reaching the mid 80s to lower 90s, possibly a bit warmer in the immediate NYC area. More clouds are expected along with scattered storms, some perhaps strong. Showers and storms will stick around through Saturday with highs in the mid 80s for most of the area, slightly cooler in some areas.


Sunday - Beyond: Sunday and Monday are expected to be mostly dry with highs generally around the mid 80s, with a few showers possible early on Sunday. The model outcomes diverge starting after Monday, with some keeping average conditions, the GFS drops a cold front through, and the ECM shows heat slowly building in. There is too much uncertainty to make any high confidence call for the longer range, although at least the next 7 days with the exception of Thursday do not appear to end up far from the average on either negative or positive side.

July 23, 2012 Brief Update


12:30 AM: Following yesterday's noon update, additional storms formed in the afternoon and evening hours, but most of the activity stayed well to the north/NW of the area, with the main afternoon/evening activity focusing over Sussex county, where two strong/severe storms were observed, although both weakened once moving past NW NJ, with the second storm producing a weakening area of light-moderate rain and thunder as it reached NYC prior to dissipating.

The cold front is still near Michigan, slowly moving towards the region, while the warm front is stuck over Connecticut into central NY state. The cold front will move through before the mid afternoon hours, although very little, if any rain is expected with the front, and temperatures are expected to be even warmer tomorrow, in the upper 80s to mid 90s across the area, including eastern areas, with a NW/WNW wind.


Forecast Update:

Mostly sunny skies and dry conditions are expected for Wednesday with highs in the mid 80s across most of the area. A stormier end to the week is expected, however, with more rain between Thursday and Saturday. A low pressure will track not far to the north of the area on Thursday and Friday with the warm front expected to move through on Thursday. The exact timing of the warm front and how far north the low pressure ends up will determine how warm temperatures get, as clouds and possible storms are expected in the morning with potential clearing in the cloud cover by the afternoon/evening. Temperatures are generally expected to end up in the mid 80s to lower 90s from NYC and further west/SW, with the warmest temperatures southwest of NYC, but if the low pressure is as north as currently modeled with enough clearing in the cloud cover, temperatures in the late afternoon may end up warmer than currently expected, perhaps up to the mid 90s. Long Island and southern CT are expected to be cooler with more cloud cover and shower activity. Humid conditions are expected as well, with higher heat index values expected in the warm sector. More information on Thursday's update will be posted with a more detailed discussion on Tuesday.

With the low pressure staying north, the majority of the rain will stay to the north of the area. Despite this, additional showers and storms are expected with slightly cooler temperatures on Friday and especially on Saturday with the low pressure stuck over the region. The GFS remains the fastest model, much more than the rest of the model guidance, and is a clear outlier in its handling of the storm, although its latest 0z run is slower with the front, likely leading to a trend towards the rest of the guidance. Rain and clouds are expected to stick around on Saturday for the region, with drier conditions returning for Monday, although some clouds/storms are still likely to still stick around for at least parts of Sunday.

Monday, July 23, 2012

July 23, 2012 Noon Update



1:00 PM: Additional Storms Expected Today


Scattered heavy thunderstorms were observed early this morning in northern parts of the area, where radar estimates show localized totals above 1 inch of rain focusing over SE NY. The cold front is still currently in the north central US near Wisconsin, gradually approaching the region. Some models, especially the short range HRRR models, showed widespread storm development taking place this afternoon, some of it severe, but at this time the regional radar is still mostly quiet with the exception of a heavy storm near Sussex county moving SE.

More scattered storms are expected to form over NY and PA over the next few hours, making their way SE into the area later by the afternoon and evening hours, although severe activity is unlikely to become widespread today for the area. The cold front will move through late tonight, with dry conditions expected tomorrow along with temperatures in the upper 80s to lower 90s for most, slightly cooler near the coast and warmer in the immediate NYC area, although some models are hinting at isolated storms late tonight with the cold front passage.


The next forecast discussion will be posted on Tuesday, with more information on the late week storm outlook.

Sunday, July 22, 2012

July 21, 2012: Storms Return For Monday


The blog will not be updated on Sunday, July 22. The next update will be posted on Monday, July 23.


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Forecast Highlights:


- Scattered storms expected for Monday, lower risk for Tuesday
- Temperatures remain in 80s for most of week, much closer to average
- Additional rain or storms likely by Friday and/or next weekend


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Today's Observations:

Following yesterday's chilly rain, with temperatures only in the 60s during the day across the area, warmer temperatures were observed today although still ending up below average, peaking in the upper 70s to lower 80s from NYC and further north/west and in the mid to upper 70s in Long Island and southern CT. Temperatures will slightly warm up over the next few days ahead of a cold front producing scattered shower/storms on Monday; although a brief cool down is expected in the mid week, additional rain and storms are likely to return by Friday and/or next weekend.


Sunday - Tuesday: Warmer, Some Storms


Partly sunny skies are expected again for Sunday with temperatures warming into the mid 80s from NYC and further north/west and the upper 70s to lower 80s for most of long Island/S CT. As a cold front approaches the region, scattered thunderstorms are expected for Monday with highs similar to those of Sunday, perhaps a bit warmer if there are more breaks in the cloud cover and less rain. Scattered storms are expected, meaning that not everyone in the area will be seeing rain, and probability of severe weather is low at this time. The timing of the cold front passage is unfavorable for heat/storms on Tuesday, as it is already expected to be southeast of the area by the afternoon hours, although temperatures are still likely to warm up into at least the upper 80s to lower 90s from NYC and further north/west with slightly cooler temperatures in Long Island/S CT with the 850mb temperatures warm enough to support these temperatures.


Wednesday - Next Weekend: Additional Rain Likely


Wednesday is expected to be dry and mostly sunny with highs in the lower to mid 80s across the area, perhaps slightly passing 85 degrees in the immediate NYC area. By the second half of Thursday into Friday, however, the models have much more differences, as the CMC and some of today's GFS runs show a scenario with some similarities to yesterday's event, with a low pressure south of the area with cloudy skies and a chilly rain affecting the area. The ECM keeps the heavier rain a bit further north with temperatures reaching at least the lower 80s for parts of the area, while other GFS runs take the low pressure well to the north, with temperatures staying in the 80s along with showers and thunderstorms. As with yesterday's event, there is still uncertainty with the forecast as the timing and location of the low pressure are subject to change, although there is a high probability of rain affecting at least parts of the area late on Thursday into Friday and perhaps early Saturday, with temperatures more likely to end up near-below average as opposed to above average. Stay tuned for more information on the late week storm outlook. The outlook for the weekend is uncertain as well due to each model handling the late week event differently, although a trough is more likely to end up affecting the region than a ridge, with no additional strong heat likely at this time.

Saturday, July 21, 2012

July 20, 2012: Drier, Warmer Weekend Coming Up


Forecast Highlights:

- Drier/Warmer Weekend Follows Chilly Rain
- More Storms Early Next Week
- Upcoming Pattern Favors Less Heat


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Today's Observations:


As a wave of low pressure developed over the Mid Atlantic region along a stalled cold front, cloudy skies and widespread showers spread across the region resulting in an unusually chilly July day, with highs only in the lower to mid 60s across most of the area during the day, slightly above 65 in some areas, which was significantly colder compared to just two days ago when temperatures soared above 100 degrees in the immediate NYC area. The usual high/low temperature times were the opposite of the usual; actual high temperatures were observed around 12-5 AM, peaking in the upper 60s to lower 70s before dropping into the 60s by the morning hours. Meanwhile, low temperatures were observed for most either late at night or during the middle of the day.

The main highlight of the day was the rain event, as it ended up unfolding differently than the expectations. The model guidance never had a solid handle on the event from the start, leaving some room for error, especially with the axis of heavy rain which remained uncertain through the short range, as the model guidance generally pointed to the heaviest rain staying west and south of NYC with some models showing it north of NYC but not too far north. Locally heavy rain did end up in southern/central NJ and parts of western NJ, but the axis of heavier rain was well north of the expectation, ending up as far north as the Connecticut/Massachusetts border. Some model runs didn't even had rain making it that far north. There were hints of a further north axis of heavier rain with yesterday's radar when the steadier rain was further north than modeled. The rain also came in earlier than some models showed, as the ECM/GFS were moderately slow with bringing the rain in while the NAM was too slow, with the rain only starting in the morning for most. The rain was supposed to last throughout the day today and into parts of the overnight hours. Instead, the rain already started in the middle of the overnight hours and ended west of NYC as early as 3 PM. In the early afternoon hours. Rain totals ended up close to the expectation, however, with totals locally above 1 inch.


Weekend Outlook: Drier, Warmer


Clouds will stick around in parts of the region on Saturday, although clearing is expected for other parts including the area, with partly sunny skies expected for Saturday along with temperatures warming up into the upper 70s to lower 80s for most of the area, a bit cooler in eastern areas and warmer in the immediate NYC area. Partly cloudy skies are also expected for Sunday with highs in the lower to mid 80s across most of the area with upper 70s to lower 80s further east. Parts of the immediate NYC area may pass 85 degrees.


Next Week: Warmer, More Storms


Temperatures on Monday are likely to be similar to those of Sunday, in the lower to mid 80s, with partly to mostly cloudy skies and scattered thunderstorms. The next cold front will move through the area on Tuesday with additional scattered thunderstorms possible along with highs in the mid 80s to lower 90s across the area, with the warmest temperatures in the immediate NYC area and the coolest temperatures further east. At this time, there does not appear to be a widespread risk of severe storms. Following the cold front, temperatures will cool down into the lower to mid 80s for highs on Wednesday and perhaps Thursday. By the late week into next weekend, temperatures are likely to warm up a bit, but the upcoming pattern, although still not a persistently chilly one in the region, favors less heat in the region compared to the first 20 days of the month, with less frequent 90s. Some models show the next risk of rain to be around Friday and/or the weekend, although this far out there is still some room for changes.

Friday, July 20, 2012

July 19, 2012: Chilly Rain Tomorrow


Forecast Highlights:


- Much cooler tomorrow with rain; highs in 70s with locally heavy rain
- Gradual warm up throughout weekend
- Highs in mid-upper 80s return next week with more storms


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Today's Observations:


Mainly cloudy skies were observed today with scattered showers, locally heavy, especially in the morning and early afternoon hours. Cloud cover held much longer than expected today, and as a result temperatures were much cooler than expected, with afternoon temperatures in the mid to upper 70s across the entire area. For parts of the area, however, the high temperatures were observed in the early overnight hours as temperatures were still cooling after yesterday's 100 degree heat.

The regional radar from late this evening posted to the left shows steady light to moderate rain slowly entering the western parts of the area. As a wave of low pressure forms along the stalled cold front, periods of light to moderate rain, locally heavy, will continue tonight and throughout most of Friday, with amounts locally above 1-2 inches along with chilly high temperatures, only in the upper 60s to mid 70s. Temperatures will gradually warm up by the weekend, with temperatures returning into the mid to upper 80s by next week with more storm chances.



Friday - Weekend: Rainy, Then Drier


A wave of low pressure is slowly forming in the Mid Atlantic region and will slowly move east, spreading widespread rain throughout the northern Mid Atlantic on Friday. Additional rain is expected to build in behind the current area in southeastern NY, although this is a case where the models have difficulty handling the exact location of the narrow axis of heavy rain; some of today's models shifted south with the rain, some of them so far south that NYC was barely on the northern edge of the rain, yet the latest radar shows the rain focusing to the north of NYC. There are still some short range minor uncertainties, although more rain is now expected for the interior areas, especially over western NJ and SE NY, with localized amounts above 1-2 inches. The light-moderate rain will continue throughout most of Friday, with southern CT less likely to see rain and places west (northwest and southwest) of NYC more likely to see heavier localized totals. There are still some short range uncertainties, however, and short range updates will be posted on Friday. High temperatures are expected to be in the upper 60s to lower 70s in the areas that end up under the steadier rain for most of the day, with lower to mid 70s further east.

With the wave of low pressure moving out, drier conditions will return for most of Saturday as well as Sunday, with partly sunny skies and temperatures warming up into the upper 70s to lower 80s on Saturday and the lower to mid 80s on Sunday.


Next Week: Warmer, More Storms


The next cold front will approach the region on Monday, with highs expected to warm up into the lower to mid 80s across the area with parts of northern NJ and NYC reaching the upper 80s if there are less clouds than expected. Scattered showers and thunderstorms are expected on Monday and Tuesday, with slightly warmer temperatures on Tuesday. Another trough will move into the region by the middle of next week with highs likely returning into the upper 70s to mid 80s range before likely warming up again towards the end of next week. Stay tuned for more information on next week's outlook.

Thursday, July 19, 2012

July 18, 2012: Heat Wave Over, Cooler Temps Return


Forecast Highlights:


- Cloudy, chilly, rainy on Friday; highs to struggle passing 70-75°
- Drier, warmer weather returns by weekend


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Records set/tied today:

LaGuardia, NY
101 degrees (previous record: 100 degrees - 2006)
JFK Airport, NY
96 degrees (previous record: 95 degrees - 2010)
Bridgeport, CT
95 degrees (tied record: 95 degrees - 2006)
Newark, NJ
104 degrees (previous record: 100 degrees - 1982)

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Today's Observations:


The hot pattern observed since June 20 with only a few occasional breaks ended today with the peak of the entire heat wave, with both the hottest day of the year as well as one of the stormiest days of the year. Temperatures quickly warmed up in the morning, but the warming continued faster and longer than expected straight through 2 PM in some areas, allowing for warmer than expected temperatures peaking in the upper 90s inland, lower to mid 100s in the immediate NYC area, and lower to mid 90s in southern CT and Long Island. Humid conditions were observed as well with dew points in the 70s, resulting in heat index values as high as 108 degrees.

The heat was not the only highlight today, as widespread thunderstorms affected the area, some of them severe. Activity started today with a line of training storms over the NY/NJ line moving into SW CT, followed by more widespread storm development over western NJ focusing over Sussex county, where strong winds, heavy rain and hail were observed with some of the storms. While that was taking place, widespread strong storm development took place over NYC with the storms training in place, resulting in frequent cells moving through including heavy rain and hail, even reported in parts of Manhattan, with localized rain amounts above 2 inches resulting in flash flooding. Storms also trained over parts of Nassau county, especially further north, with strong winds and flash flooding due to heavy rainfall. Power outages and tree damage were observed in the harder hit areas as a result of the storms, mainly in the areas previously mentioned as well as other areas in New Jersey, SE NY and Connecticut. Other parts of the area, such as parts of northeastern NJ, eastern Long Island and coastal CT, missed out on the storms and generally had close to a tenth of an inch of rain.

Temperatures will return to normal behind the cold front as the pattern becomes colder than it has been so far this month; Friday will even end up much cooler than normal, with highs only in the 70s and even the upper 60s for some places. Temperatures will warm up back to normal or slightly above afterwards, although a cooler pattern will develop which will prevent widespread 90s across the region through the foreseeable range.


Thursday - Friday Outlook: Much Cooler, Rainy


Following the cold front, mostly cloudy skies are expected on Thursday with scattered showers and highs reaching the lower to mid 80s across most of the area, with upper 80s in parts of the immediate NYC area and cooler temperatures further east. Friday will be much cooler, however, as there is a growing consensus for a wave of low pressure to form along the stalled front and move east with the actual low pressure staying south of the area, resulting in widespread periods of rain with cloudy skies and chilly temperatures, only in the upper 60s to lower 70s north and west of NYC and in the lower to mid 70s from NYC and further east. There is still some uncertainty on exactly where the heavy rain axis sets up, although at this time it appears to be west and south of NYC. In this axis of heavy rain, amounts above 1 inch of rain may be possible. The exact axis of rain is still subject to some changes, however, thus resulting in some slight uncertainty with the temperature outlook as well. Any changes in the forecast will be mentioned with Thursday's update.


Longer Range: Warming Up, But Not As Hot


Temperatures will slowly warm up by the weekend, reaching the upper 70s to lower 80s across most of the area on Saturday and the lower to mid 80s by Sunday. Dry conditions are expected for both days as the wave of low pressure moves offshore. Temperatures are likely to continue warming through Monday and Tuesday, with more widespread highs in the mid to upper 80s, perhaps reaching 90 degrees on Tuesday, ahead of a cold front expected to move through sometime around the middle of next week with a risk of showers and thunderstorms. This will prevent another heat wave from developing, with temperatures expected to remain generally close to average. Stay tuned for more information on the outlook for next week.

Wednesday, July 18, 2012

July 18, 2012 Storm Updates


Below, updates will be posted on the severe storms expected to affect the area today.

Link to 7/18 discussion, including an overview of today's storm activity

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More storm updates from 7/18 can be found in the NYC Area Weather twitter page.


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Blog Updates: (Scroll down for morning storm outlook)


6:50 PM: Additional afternoon storm development took place, with NYC the main target for the strong storms as a line of heavy storms trained over the city, producing amounts locally near/above 2 inches along with reports of hail in Manhattan. Other than NYC, northern Nassau county and Sussex county also got hit hard with storms. While some areas got hit hard, others did not see as much activity, such as parts of northeastern NJ, coastal Connecticut, and eastern Long Island.

This is the last storm update for today. A review of today's storms will be posted tonight along with an updated forecast discussion regarding Friday's outlook, which is looking wetter and colder than previously thought, with highs only in the mid 60s to lower 70s in interior areas along with periods of rain.


3:35 PM: Since the last update, the line of severe cells weakened, with new storms forming in northern NJ around I-80 moving east/ESE. The squall line from central NJ is now extending north into Warren and Sussex counties, with severe storms forming along that line. Currently that line is up to southern Sussex putting the corridor up to NYC in its axis, but if it extends north it will affect the rest of NE NJ as well. The main risk remains heavy rain, strong winds and hail.


2:55 PM: There is a stationary line of training cells extending from NE PA through the NY/NJ border and into southern Connecticut. The strongest storms are in Connecticut, where some storms are severe with hail, strong winds and heavy rain, although some storms in the stationary line further west are severe as well. Currently almost the entire I-80 axis from NE PA into NYC is dry with no storms forming overhead; observations over the next few hours will reveal whether more storms will form along this axis or not.


1:50 PM: Cluster of severe storms has developed over NW NJ/Orange county in NY, moving east/ESE. These storms will affect Rockland and Westchester counties in SE NY over the next 1-2 hour, producing hail, strong winds, and localized flash flooding with over 1 inch of rain. The storms will also affect the northern edges of Passaic and Bergen counties in NE NJ.

Additionally, there is a strong storm over northern Nassau county in Long Island, also capable of producing hail, strong winds and heavy rain. This storm will move east into NW Suffolk county.


1:20 PM: Isolated storms popped up in the immediate NYC area over the last 1/2 hour, with hail observed in parts of Westchester county. A small storm also affected parts of Bergen county and Bronx. The latest radar shows more widespread storm development near NW NJ and interior SE NY which is moving east/ESE. Additional storms will continue to form and intensify this afternoon resulting in more widespread strong/severe storm activity for Connecticut, northern NJ, NYC and Long Island.



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12:25 PM Heat Update


With partly sunny skies, temperatures continued to quickly warm up and have exceeded the forecast, reaching 99 degrees in Teterboro and 101 degrees in Newark. This breaks Newark's previous record of 100 degrees set in 1982. Due to the humidity, heat index values are much higher, near 106-107 degrees. Temperatures are still warming up, and may get even higher by 1 PM.


Elsewhere, Central Park and LaGuardia are near 98 degrees. Long Island is cooler with temperatures near 91-93 degrees, but with higher dew points as high as 75-76 degrees, heat index values are as high as 105 degrees.




11:25 AM: Strong/Severe Storms This Afternoon


Scroll down to the bottom for the latest storm updates


Widespread heat was observed yesterday across the region as a surge of warmth moved into the region. A cold front will push the warmth out of the area, and even bring much cooler highs only in the 70s for Friday, but not before strong to severe storms associated with the cold front affect the area.

Temperatures are already quickly warming up despite the time of the day, with temperatures as of 11 AM already in the lower to mid 90s, as expected from yesterday's forecast. Along with dew points in the lower 70s, heat index values are already near/slightly above 100 degrees. Newark leads the tri-state area OBS with 96 degrees and a dew point of 71 degrees, with a heat index of 103 degrees. Temperatures will continue to rise through at least 12-1 PM, allowing highs to reach the upper 90s in parts of the area.

The cold front is currently located near central New York state, slowly moving towards the area. There is a warm and unstable air mass ahead of the front, which will fuel widespread thunderstorm development across the region today. The best parameters are focused over southern New England down to Connecticut and SE NY, where lift index is already near -8 with CAPE up to 3500 J/kg. Unlike other parts of the region, there is also higher bulk shear over southern New England, and as a result, I placed the highest risk of severe weather over the NYC area and north/NE, into southern New England.

The best risk of severe weather development is over southern New England, north/NE of NYC, although these storms will later drop into NYC/northern NJ/parts of Long Island by at least 3-5 PM, with the sea breeze boundary also perhaps adding to the severe weather chances for Long Island/NYC. The main risk with today's storms is strong wind gusts, large hail, as well as heavy rain and localized flash flooding with precipitable water values over 2 inches. There isn't a widespread tornado risk, although an isolated tornado or two is not out of the question in southern New England.

Stay tuned for more storm updates throughout most of the afternoon and evening hours, both here and on the NYC Area Weather twitter page. A forecast discussion will be posted tonight regarding the much cooler temperatures for Friday and the outlook for the longer range.



July 17, 2012: Hot, Stormy Tomorrow


Forecast Highlights:

- Hot, humid again tomorrow; scattered afternoon storms, some severe
- Much cooler for Thursday/Friday with scattered showers
- Seasonable, dry weekend expected
- Not as hot long range pattern likely to develop


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Records set/tied today:


Newark, NJ
100 degrees (tied record: 100 degrees - 1997)

LaGuardia, NY is listed at 97 degrees in some sources and 98 degrees in others. The record in LaGuardia was 98 degrees set in 2006.


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Today's Observations:


With another surge of warmth moving into the region, the NYC area observed another mostly sunny, hot and humid day, with Newark observing its second 100 degree day of the month. Temperatures peaked in the mid 90s inland, mid to upper 90s in the immediate NYC area, with JFK, Long Island and southern CT cooler, in the upper 80s and lower 90s with onshore winds. Today was the 2nd warmest day of the year for most places from NYC and north/west, behind July 7.

A cold front will slowly move into the region tomorrow, but one more day of heat and humidity, along with scattered storms, is expected before the cooler temperatures make their way into the area. A drier and seasonable ending to the week is expected, with indications pointing to less heat for the longer range.


Tomorrow's Outlook:


Temperatures will fail to drop much overnight in the immediate NYC area, failing to drop much below 80 degrees, if at all for some areas. As a result, with a partly sunny start to the day, temperatures will quickly be able to warm up, already reaching the mid 90s by 11 AM. Unlike today when dew points were in the 60s, however, dew points tomorrow will already be near/above 70 degrees, resulting in much higher heat index values. While temperatures are expected to be in the mid 90s around noon, the heat index is expected to be near/above 100 degrees.

As the cold front approaches the area, with generally favorable parameters, scattered thunderstorms are expected to form across the northern Mid Atlantic especially after 1-2 PM, which will prevent temperatures from warming up much after 12 PM. Some of the storms will be severe, capable of producing strong winds and hail, as well as downpours and perhaps localized flash flooding with precipitable water values above 2 inches. At this time, most of the area is at risk of seeing scattered strong/severe storms, although some of the latest models focus the initial storm development closer to NYC, which may result in places north of NYC seeing less storms tomorrow. An update will be posted on Wednesday morning with updates on the storm risk along with storm updates throughout the day.


Thursday - Friday: Much Cooler, Some Rain


As the previous update mentioned, the outlook for late this week changed from the previous expectation, as the front will be much slower to come through than originally thought. Thursday is still expected to be warm, with highs in the mid to upper 80s, along with scattered thunderstorms, although the more widespread storms will stay south of the area. By Friday, however, a cooler air mass along with cloudy skies and occasional showers are modeled for the area. This is quite a significant change from two days ago, when mostly sunny skies and seasonable temperatures were expected; if the models are correct, high temperatures may end up as low as only the lower 70s on Friday. The latest models complicate the outlook a bit, as perhaps some models may be slightly exaggerating the cool temperatures, although I did revise the forecast to reflect this trend, with highs in the mid 70s inland and upper 70s across the rest of the area. It is not out of the question that the forecast temperatures may have to be lowered some more.


Longer Range: Warmer, But Not As Hot


By the weekend, drier conditions are expected with temperatures warming back up into the lower to mid 80s for most of the area on Saturday with more widespread mid 80s by Sunday. While temperatures will warm up back to average, possibly a bit above average, there won't be a heat wave for the early week with the core of the ridge staying to the west and another trough approaching. As a result, temperatures will likely peak at most in the upper 80s to lower 90s in the early week before another cold front likely moves through. While the pattern for the rest of the month is not expected to be a persistently chilly one, with occasional heat still expected, it is not likely to be as hot as the first 20 days of the month were, with less frequent 90s for highs. Stay tuned for more information on the longer range.

Tuesday, July 17, 2012

July 16, 2012: Peak of Heat Tuesday, Weds


Forecast Highlights:


- Heat to peak tomorrow, mid-upper 90s NYC and north/west
- Slower front than first thought; scattered storms from Weds through Friday
- Seasonable, dry weekend expected


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Today's Observations:


Following yesterday's storms, mainly dry conditions were observed across the area with the exception of a few very isolated storms especially further inland. Temperatures were warmer as a slightly warmer air mass moved in, with highs reaching the lower to mid 90s across most of the area with upper 80s in some parts of southern CT and Long Island.

The 3rd heat wave for the region, 4th one for most of the area when including the single day that interrupted the late June-early July heat, will extend through Tuesday and Wednesday, with highs reaching the mid to upper 90s from NYC and further north/west on Tuesday and Wednesday with heat index values reaching and possibly exceeding 100 degrees. A slow moving cold front will then enter the region, with scattered strong/severe storms on Wednesday evening with additional scattered storms on Thursday and possibly Friday. Drier conditions will return for the weekend, but for the first time since mid June, there likely won't be a heat wave following the period of cooler temperatures.


Tuesday - Wednesday: Hot, Humid


The peak of the heat wave will take place on Tuesday and Wednesday with mostly sunny skies, WSW winds, and 850mb temperatures near 20-21C. Temperatures will reach the mid to upper 90s from NYC and further north/west on both days, with lower to mid 90s across most of Long Island/S CT, a bit warmer closer to NYC and cooler further east. By Wednesday in the late afternoon and evening hours, a cold front will approach with scattered thunderstorms, some of them strong/severe and capable of producing heavy rain. More information on Wednesday's severe weather potential will be posted with Tuesday's update.


Late Week - Weekend: Stormy, Then Drier


Originally, the cold front was expected to drop south of the area, with a seasonable and dry ending to the week. With the passage of the front trending slower, however, the front is expected to slow down over the area, keeping mostly cloudy skies and occasional showers in the forecast through Thursday and possibly Friday. High temperatures on Thursday are still expected to be in the mid to upper 80s for most of the area, ending up cooler in some places, with Friday's highs more uncertain due to model differences with the rain but likely to end up somewhere around the lower to mid 80s range.

By next weekend, with the high pressure moving south of the area, drier conditions are expected with seasonable temperatures, although at this time there does not appear to be a heat wave building in behind the stretch of cooler temperatures as a weak trough moves towards the region with the core of the heat staying west. While this pattern is not expected to be a persistently cooler than average one, it is expected to result in a cooler ending to July compared to the first 20 days of the month, with perhaps more rain chances. Stay tuned for more information on the longer range outlook.

Monday, July 16, 2012

July 15, 2012: Hot, Stormy, Then Colder


Forecast Highlights:


- Tuesday peak of heat; widespread mid-upper 90s, possibly 100
- Scattered storms, possibly strong, on Wednesday
- Much cooler, less humid ending to week


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Saturday, July 14 Observations:


Little changes were observed in the area compared to the previous day, with widespread cloud cover although the storm activity stayed to the south of the area. Temperatures reached the upper 80s across most of the area, with lower 90s in parts of Long Island. This was different than the previous days, when Long Island had the coolest temperatures in the area. Less cloud cover was observed further north/NE, with more widespread 90s observed in New England.



Sunday, July 15 Observations:


Mainly cloudy skies were observed today as widespread showers and storms, some of them heavy, affected the region, fueled by widespread moisture in the region with precipitable water values over 2 inches. Flash flooding was observed in parts of Orange, Rockland and Westchester counties in SE NY as well as Fairfield county in CT, where amounts were locally as high as 3 inches. Some of the storms were strong with strong winds and hail. Heavy storms were observed in southern parts of NYC, central NJ, and central Long Island, with northern NJ missing out on the storm activity with less than 1/4 inch for most places. Temperatures reached the lower 90s from NYC and further west which were not affected by the mid afternoon storms, and the mid to upper 80s across the rest of the area due to more widespread afternoon storms.


Monday - Wednesday: Another Heat Wave, Ends With Storms


The warmer than average pattern which started around June 20 with occasional periods of near-slightly below average temperatures is still in place, as the 3rd heat wave of the year will affect the area during the first half of this week. Temperatures will be a bit slow to warm up on Monday as the core of the warm air mass will still be organizing over the north central US, with highs reaching the lower 90s for most places from NYC and further north/west, with upper 80s to lower 90s across most of Long Island/S CT as well due to a WNW wind. Immediate coastal areas especially further east should be a bit cooler, closer to 85 degrees.

The peak of the warm air mass will move into the area on Tuesday, with 850 mb temperatures near 20C along with mostly sunny skies and west/WSW winds, supportive of upper 90s in parts of the area. The NAM is showing low 100s in NE NJ, the 5th time it has shown 100+ degree heat in the area this year; the first 3 times failed to verify with upper 90s instead, although the previous time the NAM modeled 100 degrees, it failed to verify further north due to more widespread cloud cover from unexpected morning showers, although Newark and surrounding areas still reached 100 degrees. In this case, I am going with temperatures slightly cooler than those of the NAM, with mid to upper 90s from NYC and further north/west, with the hottest temperatures near NE NJ, and lower to mid 90s across Long Island/S CT with areas closer to NYC near/possibly a bit above 95 degrees. More sea breeze influence is expected in Long Island/S CT with SW/SSW winds.


Temperatures will be slow to cool down overnight, staying in the 70s for most of the area, failing to drop much below 80 degrees in NYC. As a result, temperatures will be quick to rise on Wednesday morning, already reaching the lower to mid 90s in the immediate NYC area by 11 AM. The cold front will already be approaching by then, however, with temperatures failing to warm up much afterwards. Scattered thunderstorms are expected during the afternoon and evening, some of which could be strong or possibly severe, although depending on the exact timing of the front, it is possible that the best risk of severe weather may stay to the north of NYC.




Thursday - Next Weekend: Cooler, Then Warming Up


Following the cold front on Wednesday, a cooler air mass will return into the region for the late week into the early weekend. Mostly sunny skies are expected with highs on Thursday in the mid to upper 80s for most of the area, dropping into the lower to mid 80s for Friday and Saturday. Overnight lows will be in the 50s inland and in parts of Long Island with 60s elsewhere.

By later in the weekend into the start of the following week, with the Canadian high pressure shifting south of the area, a building warm air mass in the north central US will move east into the region. At this time, this appears to be more of a stretch of upper 80s and some 90s as opposed to a widespread heat wave, although there is still some time for changes with the set up given the time range. Stay tuned for more information on the longer range outlook.

Sunday, July 15, 2012

July 15, 2012 Storm Updates


Below, short updates will be posted on the heavy thunderstorms affecting the area. Live updates can also be found in the NYC Area Weather twitter page.

Today's discussion will be posted once the storm updates are over, with information on the nearly 100 degree heat coming for Tuesday, strong to possibly severe storm potential on Wednesday, and the much cooler weather that will follow. An update for the 5-Day Forecast page is in progress and will be completed by 6 PM.

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Blog Storm Updates:


Twitter updates can be found in the NYC Area Weather twitter page.



7:30 PM: The heavy storms earlier this afternoon in Orange, Rockland, Westchester and Fairfield counties resulted in areas of flash flooding, with as much as 3 inches of rain observed in 1-2 hours in some areas. Strong winds were also observed with the storms. Since then, the storms weakened as they moved into Suffolk county in Long Island.

Additional storms are moving into SE NY, with more storms in Orange County adding to the heavy rain totals observed earlier today. The heavier storms are expected to miss northern NJ, where areas of moderate rain and thunder are expected in the next 1.5-3 hours.


4:45 PM: The latest regional radar posted to the left shows widespread shower and heavy thunderstorm activity across the region. With precipitable water values above 2 inches, storms are capable of producing heavy rain and flash flooding in a short period of time. So far this afternoon, heavy storms were observed in SE NY, with amounts in Rockland, Orange and Westchester counties locally above 1-2 inches.

These storms will move into southern CT for the next few hours as additional heavy storm activity in Pennsylvania begins to enter the area. These storms will also be capable of producing heavy rain and localized flash flooding. A few storms may become strong or possibly severe, but most of the activity today will stay below severe levels.

(Updates prior to 4:45 PM were on twitter.)



July 15, 2012 Morning Update


Due to a busy schedule, I was unable to update the blog as I had originally planned. I am currently working on a forecast discussion, although it will likely be completed by the late afternoon/evening hours.

Until then, brief updates about the forecast will be posted on the NYC Area Weather tweeter page.

Saturday, July 14, 2012

July 13, 2012: Hot, Humid Start To Next Week


Forecast Highlights:

- Mostly cloudy weekend with scattered storms expected
- Short yet intense surge of heat next week; mid-upper 90s NYC and N/W
- Humidity to result in heat index possibly above 100 degrees
- Possible strong/severe storms Wednesday, cooler ending to week


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Thursday, July 12 Observations:

As a slightly warmer air mass moved in with the trough moving out, temperatures ended up slightly warmer than the previous day, reaching the upper 80s to lower 90s from NYC and further north/west. Southern CT had highs in the mid to upper 80s except for SE areas which were cooler, with Long Island in the lower to mid 80s. Partly cloudy skies were observed across the area. Newark, Central Park and LaGuardia peaked at 89 degrees, just 1 degree short of 90 degrees.



Friday, July 13 Observations:


The slightly warmer air mass continued to move into the Northeast, where widespread upper 80s and low 90s were observed. In the area, however, there was more cloud cover than expected, which resulted in slightly cooler temperatures than expected. Temperatures reached the mid to upper 80s from NYC and further north/west, with mid 80s in most of Long Island/S CT except for eastern coastal areas, which peaked in the lower to mid 80s. Newark, Central Park and LaGuardia peaked at 89 degrees for a second consecutive day.



Weekend Outlook:


Cloud cover moved into the region ahead of the original expectation, and as a result mostly cloudy skies and scattered showers and thunderstorms will continue through the weekend. The best risk for storms is on Sunday, when scattered thunderstorms are expected, some of them heavy, although this weekend will not be a widespread regional washout. Temperatures for Saturday are expected to reach the upper 80s to lower 90s from NYC and further north/west and the mid 80s to 90 degrees in most of Long Island/S CT, with temperatures on Sunday slightly cooler, in the mid to upper 80s for most, perhaps cooler further inland and/or closer to the coast, due to the storms and cloud cover.


Next Week: Hot/Humid Start, Stormy Middle, Cooler End

The heat surge mentioned with the previous update is still on track to affect the region and the NYC area, although it is expected to do so a day earlier than first thought, setting up for a 3 day stretch of hot/humid conditions from Monday to Wednesday. Temperatures will begin to warm up on Monday with partly sunny skies, west/WNW winds, and highs reaching the lower to mid 90s from NYC and further north/west and the upper 80s to lower 90s in Long Island/S CT, perhaps a bit cooler further east depending on the sea breeze. Somewhat humid conditions will result in heat index values likely reaching the upper 90s in the immediate NYC area.

The warm air mass is expected to end up over the north central US on Monday, moving into the region on Tuesday and Tuesday night. As a result, the hottest temperatures will likely be on Tuesday, with mostly sunny skies, WNW winds and 850mb temperatures near 20C. High temperatures are expected to reach the mid to upper 90s from NYC and further north/west, and the lower to mid 90s in most of Long Island/S CT, staying below 90 degrees in eastern areas closer to the coast. Humid conditions are expected again, with heat index values likely reaching and/or exceeding 100 degrees in the immediate NYC area.

By Wednesday, a cold front will move through the region, ending the heat. The exact timing of the front is still uncertain, with the slower NAM/DGEX combo and the CMC supporting widespread 90s and possibly low 100s, while the GFS and ECM models are faster, with highs barely reaching 90 degrees followed by widespread storms in the afternoon. 2 days ago the models were still too slow with the front and only recently adjusted towards faster timing, and at this time I am siding closer to the faster ECM/GFS but a little slower, with highs reaching the lower to mid 90s for most of the area with cooler temperatures further east, followed by scattered thunderstorms in the afternoon along with the potential for strong/severe thunderstorms. Stay tuned for more information on Wednesday's outlook.

Behind the cold front, a brief yet strong cool air mass will move in for Thursday and next Friday, bringing another break from the heat. Some models are probably overestimating the temperatures, which are still expected to stay in the 80s in this time frame, likely somewhere around the mid 80s, although temperatures will be back in the near-slightly below average range, with overnight lows in the 50s possible inland. After late next week there is more uncertainty although a gradual warm up is possible.

Wednesday, July 11, 2012

July 11, 2012: Above Average Temps Continue


The blog will not be updated on Thursday, July 12. The next update will be posted on Friday.


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Forecast Highlights:


- Warmth gradually builds in; some 90s possible Thurs-Sat
- Thunderstorms possible for Sunday, potentially heavy
- Additional heat, humidity expected for next week


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Today's Observations:


Today ended up once again similar to yesterday with little changes in the set up across the region, with temperatures reaching the mid to upper 80s from NYC and further north/west and the lower to mid 80s in Long Island/S CT. A few isolated storms popped up near Sussex/West Passaic counties, although the rest of the area was dry.

Temperatures will slowly warm up, with more widespread mid-upper 80s and some lower 90s expected between Thursday and Saturday. As the Bermuda high shifts west, widespread moisture and humidity are expected starting Sunday, with scattered storms, some heavy, likely on Sunday. More widespread low-mid 90s are expected for next week; although temperatures will not be as hot as they were last week, the humidity will result in higher heat index values.


Thursday's Outlook:


Temperatures will begin to slowly warm up on Thursday with slightly warmer 850mb temperatures. Mostly sunny skies are expected with high temperatures reaching the upper 80s from NYC and further north/west, mid to locally upper 80s in southern CT, and the lower to mid 80s in Long Island. Parts of NE NJ may reach and/or slightly exceed 90 degrees.


Friday - Weekend: Still Warm; Stormy Sunday Possible


As 850mb temperatures continue to slightly warm up along with mostly sunny skies, Friday is expected to be another warm day with highs in the upper 80s to lower 90s from NYC and further north/west and the mid to upper 80s in Long Island/S CT, staying below 85 degrees near the immediate coast especially further east. The warmest temperatures are expected near NE NJ. There is slight uncertainty for Saturday as some models bring in the rain faster, with cooler temperatures in the lower 80s in NYC, while others such as the NAM keep the rain further west with warmer temperatures in the upper 80s to lower 90s. For now, I'm siding closer to the warmer NAM, with highs mostly in the lower 90s from NYC and further north/west, approaching 95 degrees near NE NJ and possibly staying a bit under 90 further inland, with Long Island/S CT in the mid to upper 80s, approaching 90 degrees closer to NYC. Partly cloudy skies are expected with a risk of isolated storms late, especially into the overnight hours.

By Sunday, the highest precipitable water values will move through the area. The GFS and ECM models show widespread rain, locally heavy, while the NAM and CMC are somewhat drier and thus warmer. The coverage area of storms is still a bit uncertain; at this time, at least scattered storms are expected on Sunday for parts of the area, although storms will easily be capable of producing heavy rain. Due to the cloud cover/storms, I went with slightly cooler temperatures for Sunday, reaching the mid to upper 80s across the area, although it is possible temperatures may be revised a bit upwards should the drier outcome verify.


Next Week: Hot, More Humid


Following Sunday's scattered storm activity, Monday and Tuesday are expected to have partly sunny skies with highs reaching the lower 90s for most places north/west of NYC, possibly approaching 95 degrees in NE NJ if there's enough sunshine, with mid to upper 80s in most of Long Island/S CT and some lower 90s. Isolated storms may be possible on both days but at this time there does not appear to be any widespread heavy rain risk. More widespread humidity is expected as a result of the Bermuda high, however, with heat index values possibly reaching the mid-upper 90s.

By Wednesday and Thursday, with a trough over SE Canada failing to drop into the region, warmer 850mb temperatures will move into the region from the west, reaching at least 20C, possibly a bit higher. Temperatures are likely to warm up with widespread lower to mid 90s from NYC and further north/west and mid 80s to lower9 90s in Long Island/S CT. The exact extent of the heat is still a bit uncertain, although in the warmer case scenario the potential is there for temperatures to reach the upper 90s at least once in NE NJ. Humid conditions are expected again, which will result in the potential for heat index values to end up close to 100 degrees. The longer range outlook becomes more uncertain; the possibility is there for a cold front to affect the area late next week, although there does not appear to be any large scale relief from the above average temperatures on the way through the 7-10 day range.